Lab-on-a-Chip Works!

April
6, 2007: "What a huge relief," says Norman
Wainwright of the Charles River Laboratories in Charleston,
SC. "The whole technical team was delighted that it worked
so well."

He's
talking about a miniature biological laboratory just tested
for the first time onboard the International Space Station.
Called LOCAD-PTS (short for Lab-On-a-Chip Application Development–Portable
Test System), the mini-lab detects the presence of bacteria
or fungi on the surfaces of a spacecraft far more rapidly
than standard methods of culturing.

"The
ability to monitor microorganisms would be especially important
on long space voyages, not only to check the health of astronauts
but also to monitor electronics and structural materials,
which can be corroded or otherwise damaged by certain fungi
and bacteria," says Wainwright, the experiment's principal
investigator. LOCAD-PTS is designed so that "astronauts
can do the analysis onboard with no need to return samples
to laboratories on Earth."

The
device was launched last December 9th on board the space shuttle
Discovery, and then stowed aboard ISS until its scheduled
experiment time—which happened to be Saturday night, March
31, Marshall Space Flight Center time. (Remember that time!)

Astronaut
Sunita "Suni" Williams opened the instrument kit
bag, assembled LOCAD-PTS, and then took six readings. "The
first two readings were controls to show that the instrument
was operating correctly," explains Jake Maule, LOCAD-PTS
project scientist at the Carnegie Institution of Washington.
"First she swabbed her palm, which she had first pressed
to handrails and other often-handled surfaces that should
have had lots of bacteria—and indeed, we got a strong positive
reading," he continues. "Then she sampled some ultraclean
water in the instrument that is used to moisten samples, to
check that the water was truly clean—and indeed, we got a
great negative reading."

Next,
Williams chose a wall panel in ISS Node 1 to test using both
LOCAD-PTS and, for comparison, a standard culturing method.

For
the standard method, she pressed a layer of solid gel growth
medium (rather like agar) to the panel for a few seconds,
replaced it securely in its packaging, and then set it aside
to incubate for a few days.

Then
she took a dry swab, rather like a high-tech Q-tip, from LOCAD-PTS
and rubbed it on the panel next to the same area. Flushing
ultraclean water through the swab converted the sample to
liquid form, and a few drops were dispensed into the hand-held
LOCAD-PTS instrument.

"The
cleaner the sample, the longer the analysis takes," Wainwright
says. "Because this site was pretty clean, it took about
12 minutes, but dirty samples can take as little as a couple
of minutes."

It
was during the wait that Williams must have noted the time.
Although it was 10:20 PM Central Daylight Time at Marshall
in Huntsville, Alabama, where all the LOCAD-PTS scientists
were anxiously watching television monitors, it was actually
past midnight on April 1, Greenwich Mean Time, the time zone
used by ISS.

"Suni
said, 'Ah, this last set of readings for LOCAD-PTS looks a
bit strange,'" Maule recalls. "After a pause of
about five seconds, she exclaimed, 'Happy April Fools' Day!
The numbers are just fine!'"

"She
definitely got me!" he laughs.

Right:
Researchers in the control room at MSFC celebrate when they
hear that LOCAD-PTS has worked. From left to right: Dr. Lisa
Monaco, Tony Lyons, Dr. Jake Maule, Dan Gunter. [Larger
image]

Over
the next few months, LOCAD-PTS and standard culture methods
will be used to investigate different parts of ISS. "A
second-generation of LOCAD-PTS cartridges for the specific
detection of fungi are scheduled to launch to ISS on Space
Shuttle STS-123," says Anthony T. Lyons, LOCAD-PTS project
manager at Marshall, the NASA center that has overseen the
project since its inception and supervised getting the equipment
spaceflight-ready. "With each generation of cartridges,
we are getting more and more specific in what we detect. Our
ultimate aim is to provide the crew with a selection of cartridges
for the detection of a wide variety of target compounds, biological
and chemical both inside and outside the spacecraft—something
that would be especially important for long-duration missions
to the Moon or to Mars."